XIX] 



EMBRYOGENY 



85 



panied by the origin of the second root, which appears endogenously close to 

 the proximal end of the vascular strand of the first. Immediately above this, 

 and opposite the neck of the archegonium, the shoot appears, the cotyledon 

 being on the same side of the axis as the first root. But the cotyledon 



J-h 







^ 



Fig- 387. Ophioglossiim vulgatuin. The upper figure shows a young sporeling in longi- 

 tudinal section : w, first root with evident apical cell ; /, the foot only slightly projecting ; 

 e, the epibasal region; /, the remains of the prothallus. The lower figure shows part 

 of a large sporeling in longitudinal section: /, prothallus; w, first root; k, entering 

 fungal filament ; e«, endophytic fungus ; aw, insertion of second and third roots; j-, apex 

 of rhizome; p\, p-i, p-i, leaves; c, canal; hi, hi, sheaths of leaves. (After Bruchmann 

 (X35)-) 



remains rudimentary, and is followed by a second leaf which may develope 

 as a small sterile leaf expanded above ground. The third leaf may under 

 favourable circumstances bear a fertile spike. The further development then 

 follows as in the adult plant. 



Campbell, having examined several tropical species of Ophioglossiwi, recognises three 

 types of embryogeny in the genus: that of O. vulgatum above described: that of 



